The present invention relates to an electrically conductive Si.sub.3 N.sub.4 -C series amorphous material and a method of producing the same.
Recently, there has been interest in silicon nitride Si.sub.3 N.sub.4 as a high temperature structural material and an electrically insulative material.
In U.S. Pat. No. 4,036,653, there is disclosed an amorphous nitride composition consisting essentially of from 95.0-99.9% by weight of amorphous silicon nitride and from 0.1-5.0% by weight of carbon prepared by the vapor phase reaction of silicon tetrachloride, ammonia and a gaseous hydrocarbon at temperatures from 1,000.degree. to 1,500.degree. C. However, the amorphous nitride composition is obtained only in an impure powder form as described in Example 1 of the U.S. patent, so that it cannot be produced in a massive body without purification and sintering. Thus, massive and pure amorphous silicon nitride containing carbon is not old.
In U.S. Pat. No. 4,118,539 filed by one of the inventors of the present application, there is disclosed a production of superhard silicon nitride having an industrially usable massive size and large thermal shock resistance by a synthetic process of chemical vapor deposition (CVD). The Si.sub.3 N.sub.4 of the U.S. Pat. No. 4,118,539 has a high thermal conductivity, an excellent thermal shock resistance property and a high hardness not only at low temperatures but also at high temperatures, so that it is a useful material at high temperatures. In addition, its electric resistance is so extremely large that it is also useful as an electrically insulative material in the electrical and electronic industry. Meanwhile, if it is imparted with an electrical conductivity, vast uses can be expected as a high temperature electric material and a high hard electric material.